How BIM can be useful in small buildings. Considering the cost for BIM implementation is quite expensive, starting from infrastructure/hardware, software, and training.
BIM research in a broad field. You can study the latest publications to find out about the state-of-the-art of BIM. existing studies normally make recommendations for future study, which can be helpful in developing new ideas.
Moreover, you may contact university professors with research interest in BIM to discuss new ideas (if you are going to apply to PhD position at a specific university.)